Hypertext linking has radically simplified the manner in which users interact with computers. With hypertext linking, links are defined between a source location in one document and a target location in the same or another document. A user navigates from the source to the target typically by selecting a hypertext link definition at the source location. In addition, a hypertext link definition can be associated with a particular object displayed in a document so that the associated object may be selected by a user to activate a hypertext link.
By associating hypertext link definitions with displayed objects, an extremely powerful, efficient, and intuitive interface is provided to a user. As an example, a document may include hypertext links between selected words and their definitions. A user reading that document may then be able to pull up definitions of particular words that he or she does not understand by merely selecting those words directly. In a typical graphical or windows-type computer system, selection may be performed quickly and easily by moving a pointer over a specific word using a mouse and then clicking a button on the mouse—a concept known as “clicking on” an object.
Hypertext link definitions may be associated with a wide variety of display objects such as text, images, sounds, animation, and video clips, among others. One segment of the Internet, the World Wide Web, relies extensively on hypertext linking to permit users to navigate between documents that contain a wide variety of such multimedia objects. Documents are formatted using a standard language known as the Hypertext Markup Language (HTML).
Users typically view documents from the World Wide Web using a computer software application (known as a browser) that is configured to read this specific document format. A browser typically incorporates at least one graphical window that displays all or a portion of a particular document. The window may also include a scroll bar that a user manipulates to scroll through different portions of a displayed document.
It is in large part the simplicity and intuitiveness of hypertext linking that has made the World Wide Web the most popular segment of the Internet for many users. In addition, hypertext linking has enjoyed such popularity on the Internet that many private computer networks are set up as intranets that use the same hypertext linking concepts to organize and permit access to information stored on a company's network. Hypertext linking concepts are also used with many help systems, and have even been incorporated into the basic user interface mechanisms of some operating systems.
Many conventional browsers highlight text-based hypertext link definitions using different formatting for the word or words associated with each definition. As an example, a hypertext link definition may be highlighted through underlining and/or by portraying the text in a different color than the surrounding text. Different colors may also be used with hypertext link definitions to distinguish between those that point to previously-viewed documents and those that point to new documents, so that a user is less likely to inadvertently take a link to a document that he or she has already visited.
Hypertext link definitions may be categorized into external and internal hypertext link definitions. An external hypertext link definition links together two different documents, while an internal hypertext link definition links together two different locations within the same document. With conventional browsers, however, most users are unable to readily distinguish between external and internal links without actually taking the individual hypertext link definitions.
It is often frustrating for many users when they discover that a particular hypertext link that they have taken leaves them at a different location within the same document—and often at a location that they have already viewed. Moreover, other users may realize that they have taken an internal hypertext link to a previously-viewed location in a document only after they have read some of the information at the new location. Conversely, other users may desire to stay within a particular document and avoid taking external hypertext links, since navigation to external links is often slower than to internal links. Navigating between hypertext links therefore can become a tedious and time consuming trial and error process.
It is often desirable to maximize the time a user is viewing documents while minimizing the time a user is navigating hypertext links. This desire is even more prominent when the effects of network congestion (which can slow retrieval of new documents as well as of updates to existing documents) are considered. Avoiding navigation to undesired hypertext links would therefore eliminate a significant source of user frustration and lost productivity.
More sophisticated users having a detailed knowledge of HTML may be able to determine whether a link definition is for an internal or external link by referring to the location of the target of the link definition that is displayed in a pop-up window or status bar of some browsers when a mouse pointer is positioned over the link definition. A Uniform Resource Locator (URL) address is often displayed for documents from the World Wide Web, and filename and directory information is typically displayed for documents stored on a private network or a user's local computer. For the casual user, however, the information displayed about a target location is often meaningless.
Therefore, a significant need continues to exist for a manner of improving the efficiency of hypertext linking, particularly through minimizing the navigation of undesired hypertext links.